Medium severity · published Dec 9, 2020
CVE-2020-26956
In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS
6.1
CVSS
1.2%
EPSS
No
On KEV
Description
In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)1.2% · higher than 69% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 83.0 · source: NVD
FE
Firefox Esr · Mozilla
before 78.5 · source: NVD
TH
Thunderbird · Mozilla
before 78.5 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2020-26956
CVE.org
https://www.cve.org/CVERecord?id=CVE-2020-26956
Issue Tracking
https://bugzilla.mozilla.org/show_bug.cgi?id=1666300
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-50/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-51/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-52/
More from Firefox
10.0
CVE-2019-11708
Mozilla Firefox and Thunderbird Sandbox Escape Vulnerability
9.8
CVE-2024-9680
Mozilla Firefox Use-After-Free Vulnerability
9.8
CVE-2010-3765
Mozilla Multiple Products Remote Code Execution Vulnerability
9.6
CVE-2022-26486
Mozilla Firefox Use-After-Free Vulnerability
8.8
CVE-2023-5217
Google Chromium libvpx Heap Buffer Overflow Vulnerability